Sharp Aquos LC-32D40U - no image

[retiredcaps]

Re: Sharp Aquos LC-32D40U - no image

Pins 1, 2 and 3 are shorted to ground, but pins 4 and 5 are not. According to the datasheet you linked to, 4 and 5 should be GND?

3 other datasheets from 3 different companies for 4422 all have the same pinouts.

[electronicsurplus]

Re: Sharp Aquos LC-32D40U - no image

ahickman,

Try doing this to put the television into service mode

1) Unplug the television for a few minutes to let the capacitors drain

2)hold down the volume - and the Input at the same time

3) Plug the television in

your television should turn on and display a "K" on the screen. if this works then you most likely have a failing inverter

The television sometimes will remain working until you unplug the television

This puts the television into service mode and, will allow you to test and monitor voltages to determine the actual problem


Electronic surplus

[ahickman]

Re: Sharp Aquos LC-32D40U - no image

No "K" on screen. Tried input + vol(-) and vol(+).

[ahickman]

Re: Sharp Aquos LC-32D40U - no image

There's a few test points on the t-con that you should check the voltage on:
VCC+5V, VDD, VGL, VGH, SDRAM_VDD, VLS, 3V, SSC_VDD, D-VDD, and S_VDD(?)
Check with respect to ground. Let me know what voltages you get.

I went ahead and orderd a replacement T-con from ShopJimmy. Plugged it up and all is good. Took the time to re-measure the voltages Momaka was interested in on the new card:

Vcc = 4.92v
VGL = -6.31 v

SDRAM_VDD = 2.96 v
VLS = 14.69 v
3V = 2.99 v
SSC_VDD = 2.96
D_VDD = 2.95

[retiredcaps]

Re: Sharp Aquos LC-32D40U - no image

What about U300, pin 13, the one that was 5% out?

[momaka]

Re: Sharp Aquos LC-32D40U - no image

What about U300, pin 13, the one that was 5% out?

Yes, now that we know that the old t-con was bad, it would indeed be interesting to troubleshoot the old t-con.

Unfortunately, this t-con is very different from others I have seen, so I have a hard time telling what U300 does. Normally, a chip like that is used to generate VDD, VGL, and VGH on other t-cons (those 3 voltages are standard, although other t-cons may give them different names such as AVDD, VEE, and VGE or VDD, VOFF, and VON). Perhaps that chip is used to generate the other voltages as well - if that's the case, then replacing U300 may solve the problem. Before doing that, though, I would say check every ceramic capacitor in the power section of the t-con for short circuit. That would be everything in the upper-right corner above the "Etrontech" RAM chips in this picture:
https://www.badcaps.net/forum/attach...4&d=1341582445
If any of those capacitors read less than 50 Ohms, let me know which.

Also, if you see any bumps, holes, or other irregularities on top of any of the MOSFETs, they are likely bad. Your pictures are excellent, but such irregularities are hard to notice even with very very high quality images.

Sorry for the late reply.

[diodo49]

Re: Sharp Aquos LC-32D40U - no image

Well to whom may still interested to fix this issue.

NO PICTURE HAS SOUND

CLEAN THE 3 RECTANGULAR COPPER CORNERS OF THE INVERTER.

AND USE LOCKTITE WHEN INSTALL THE SCREWS.

THESE SCREWS CAME LOOSE WITH THE TIME.

[Nascar]

Re: Sharp Aquos LC-32D40U - no image

Thank you diodo49 your suggestion it worked perfectly for the (NO PICTURE HAS SOUND
) I could see on the casing and the inverter board were the connection was bad buy the black spots although this did solve the no video issue I did not reuse any the original screws I seen where they had already had blue locktite on them (either from the original installer or from a previous repair)and only the three that you mention were actually lose (they are to the inside) I used some used screws that had small washers and lock washers already on them (they are made this way so that the washers and lock washers do not fall off the screws) so hopefully this issue should not return (I also used a file on the case side as to try and make the raised surface have more contact to the inverter board and some emery cloth on the inverter side) I had researched this issue before and seen another post on Google were someone had said a tech from best buy fixed this issue (no video) in a small amount of time but without your post I would not have known were to look thanks for your post

on another post in this same section ahickman has posted a inverter board mine looks similar but the copper area that diodo49 refers to and on mine is on the underside of the inverter board not the top